Cardiovascuar and Respiratory Systems Flashcards
Diastole
Relaxation phase 0.5
Systole
Contraction phase 0.3
The hearts ability to fill is dependent on…
- Venous return (blood returning to the heart)
- Ventricles (able to stretch more and enlarge)
The hearts capacity to empty is dependant on…
- a greater EDV provides more stretch
- increase the force of ventricular systole
Combined they increase ventricular contractility.
Ventricular contractility
Capacity of heart ventricles to contract, causes almost all of the blood to be ejected
The cardiac cycle
The impulse starts at the SA node which involves the pace maker which initially starts off the impulse. Then the impulse is passed to the atrial walls which allow the contraction to occur. Then the impulse is passed on to the AV node which delays the impulse allowing the atria to fully contract. Then the impulse is passed to the bundle of HIS and is split into the left and right branches speeding up the impulse. Finally the speeded impulse is passed to the purkinje fibres which allow the ventricles to contract.
pulmonary circulation
deoxgygenated blood from the right ventricle of the heart to the lungs and oxygenated blood back to the left atrium.
systematic circulation
oxygenated blood from the left ventricle to the body tissues and deoxygenated blood back to the right atrium
arteries/arterioles
transport oxygenated blood away from the heart towards tissues/muscles.
capillaries
bring blood directly in contact with the tissues where oxygen and CO2 are exchanged
veins/venuoles
transport deoxygenated blood back to the heart
structure of capillaries
one cell thick layer, allow gaseous exchange
structure of veins/venuoles
thin muscular layer, allowing them to venoconstrict and venodilate at a lesser extent.
structure of arteries/aterioles
smooth ring of muscle surrounding the entry to the capillaries.
starlings law of the heart
stroke volume is dependant on venous return, if vr increases then sv increases.
